M915A4R2 Build and Modification Thread

[chucky]

Only issue with the air ride swap and using axles from one is the gear ratios.. most are 3.55s to 3.90s.

The 915a4s use the same axles as the 915A0. A 4.44 so it would lose some of its low end grunt.

Top speed would increase about 17mph

Tne 3.55 on 22.5 with an 18 sd put you at about 1400 rpm and 70 mph

 

[chucky]

Why couldnt you use your 4.44 axle housings should bolt rite up under a pete air track system ! keep your low gearing if you need it and get a good ride.

 

[simp5782]

Tne 3.55 on 22.5 with an 18 sd put you at about 1400 rpm and 70 mph

These are already double overdrive allisons. Which is equal to an RTOO14613. They will run 111 in their stock form with the governor turned to 2450.

They don't need a $5000 18 speed.

 

[chucky]

These are already double overdrive allisons. Which is equal to an RTOO14613. They will run 111 in their stock form with the governor turned to 2450.

They don't need a $5000 18 speed.

I wasnt saying to get an 18 i was giving you a rpm vs speed of the 3.55

 

[simp5782]

Tne 3.55 on 22.5 with an 18 sd put you at about 1400 rpm and 70 mph

Also Operating a big cam below 1700rpms means you want to replace some liners. They are not a low rpm motor when working

 

[chucky]

Also Operating a big cam below 1700rpms means you want to replace some lines. They are not a low rpm motor when working

Copy that i always had cats and used to 14 to 16 all the time to get good mpg hadnt been behind a cummins since i was 17 in my dads truck little cam 400

 

[chucky]